The invention relates generally to bishydroxyphenyl-functionalized monomers that contain trifluorovinyloxy moieties, and copolymers of those monomers.
Solid polymer electrolyte membrane (PEM) fuel cells have attracted significant attention as a reliable, clean source of energy, in particular for transportation and portable devices. Hydrogen PEM fuel cells generate electricity that can be converted to power through the electrochemical coupling of hydrogen and oxygen and leave water as the product. Fuel cell technology has made significant progress over the last forty years; however, a state-of-the-art fuel cell device with wide ranging applications has not been demonstrated. A key to enabling fuel cell technology lies in discovery of novel, high-performance membrane materials.
Currently, fuel cell membranes are too expensive, exhibit poor chemical, mechanical, and thermal properties, and/or demonstrate insufficient conductivities under the necessary temperature and humidity requirements (0.1 S/cm at 80° C. and 50% relative humidity) to be commercially viable. For example, the cost of NAFION®, the current benchmark membrane material, is an order of magnitude higher than the $2/kW specified by current cost targets. Furthermore, NAFION® suffers from poor performance at high temperatures and low relative humidities.
One obstacle to achieving a highly conductive and mechanically stable PEM is effective water management. Paradoxically, high levels of sulfonation are required to facilitate the movement of protons and water, yet excessive sulfonation leads to extreme membrane swelling, poor solubility properties, and mechanical deformation. Therefore, there remains a need for a means to provide the necessary mechanical integrity necessary to minimize membrane swelling while allowing high concentrations of sulfonation and consequently, elevated levels of pro ion conductivity.